106748: "Mac OS X: Troubleshooting a Dial-Up/PPP Internet Connection"
106871: "Mac OS 8, Mac OS 9: Troubleshooting a Dial-Up/PPP Internet Connection"
When using a dial-up modem, it should be considered normal if you occasionally lose a connection, given the nature of phone lines and typical operating conditions. An "unreliable" connection would be when disconnects occur more frequently, often shortly after the connection has been established.
Important: Be sure you are not perceiving the "disconnect if idle" feature as a phone line issue. The "disconnect if idle" feature allows you to specify that your modem will automatically disconnect when you do not use it for a certain number of minutes, thus freeing the line for use by others. If the disconnect always occurs after a specific interval of time (such as 10 minutes), or only after a period of inactivity, you may simply need to adjust this setting. Additionally, your Internet service provider may have its own "disconnect if idle" setting, which is beyond your control. If you seem to be disconnected after a fixed interval, then you should ask your Internet service provider what its idle disconnection policy is. The following steps describe how to check your idle disconnect setting.
Mac OS 8 and 9
- 1. Open the Remote Access control panel (or PPP control panel in some earlier versions).
2. Click the Options button.
3. Click the Connection tab (see Figure 1).
4. Click the "disconnect if idle" checkbox to disable it if necessary, or enter a larger number.
Figure 1: Remote Access control panel options--Connection tab.
Mac OS X:
- 1. Open System Preferences.
2. Click the Network icon.
3. Choose Internal Modem from the Show pop-up menu (the Configure menu prior to version 10.1).
4. Click the PPP tab.
5. Click the PPP Options button.
6. Click the "disconnect if idle" checkbox to disable it if necessary, or enter a larger number.
Once you have verified that the "disconnect if idle" feature is not the cause of your disconnects, you should troubleshoot your phone line.
Checking for phone line interference and distortion
The telephone network path between modems must be sufficiently free of noise and frequency distortion to permit a stable connection. The modem analyzes these line impairments as they affect the quality of the transmission signal. Poor signal quality causes transmission errors, reduced throughput, reduced connection speed, and dropped connections.
a. Experiment with eliminating potential sources of line impairments in the home:
- Any device connected to any telephone outlet, especially if used by the modem, and even if on a different line: telephones, including cordless telephones and their base stations, answering machines, fax machines, caller ID boxes, and other modems
- Telephone line splitters, cable extenders, faulty or overly long telephone cables (shorter is better)
- Surge protectors, including those that offer telephone line protection
- Alarm systems, especially those that are connected to the telephone system
- Computer equipment, including speakers
- Fluorescent light fixtures and light dimmers
- Satellite dish receivers
- Appliances such as air conditioners, refrigerators, dryers, microwave ovens, and televisions
- Any AC power source and related cabling
- All other things electrical, including problems with the premises wiring: loose or corroded connections, too many splices or bridges, insulation deterioration and exposed wiring, non-twisted pair telephone wiring
Start with a direct, unobstructed, modem-to-outlet connection using a short, high-quality telephone cable. As a way of confirming the problem prior to isolating it any further, there is the option of testing with a direct connection to the external telephone box located at the back or side walls of the residence. It provides one or more standard telephone jacks supplying the home telephone connections but bypassing most impairments inside.
b. Listen for noise. Because the telephone company is only obligated to provide voice-quality phone lines, it is unlikely to address the many and varied off-premises sources of line impairments that can affect the connection but don't cause audible noise. Connect a telephone to the wall jack used by the modem, then pick up the line, dial the number 1 to stop the dial tone, and listen. Contact the telephone company if the line is not quiet (loud hiss, pops, static, voices), but first disconnect other telephone devices and check again.
c. Use a local dial-in number to your Internet Service Provider. Long distance and 800 numbers aren't typically a concern, but may cause the call to be routed through more facilities, indirect paths, and different carriers with different types of equipment and lines. Local calls may be auto-forwarded in the same manner, but most reputable ISP's don't engage in this practice.
If daunted by these varied and uncertain possibilities, consider carrying the computer to a local Apple service provider for testing on analog lines of confirmed quality.